Resins stabilized with a nickel,chromium or cobalt chelate



3,459,703 RESINS STABILIZED WITH A NICKEL, CHRO- MIUM OR COBALT CHELATE Peter James Briggs and Ronald James Hurlock, Manchester, England, assignors to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain No Drawing. Filed Oct. 17, 1966, Ser. No. 586,947 Claims priority, application Great Britain, Oct. 10, 1966, 44,655/65 Int. Cl. C08f 45/62, 51/62 US. Cl. 260-45.75 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the stabilisation of polymers and more particularly to stabilisation by certain metal complexes derived from aromatic oximes containing phenolic groups.

It has now been found that complexes from certain metals and certain aromatic oximes containing phenolic hydroxyl groups wherein a chelate ring is formed containing the oxygen atom of the phenolic hydroxyl group, the nitrogen atom of the oxime group and the metal are valuable stabilisers for polymers against degradation by light.

According to the invention there is provided a process for the stabilisation of polymers against light which comprises incorporating into the polymer a chelate complex of nickel, cobalt or chromium with an aromatic oxime containing a phenolic hydroxyl group.

As polymers which may be stabilised in this way there may be mentioned for example polyolefines such as polyethylene, polypropylene, and poly-4-methylpent-1-ene, polymers such as polyvinyl chloride, polyformaldehyde, and condensation polymers such as polyamides for example polyhexamethyleneadipamide.

The chelate complex may be incorporated into the polymer in any conventional manner, for example by dissolving the chelate complex in a low-boiling solvent and, after thoroughly mixing the solution with the polymer in powder form, evaporating the solvent; or 'by means of mechanical mixing; or by extrusion compounding.

The chelate complex should be present in the polymer in amount from 0.01 to 5%, and preferably from 0.2 to 1%, by Weight of the polymer.

The chelate complex may be used alone or may be used in conjunction with other conventional additives to the polymers, for example antioxidants such as phenolic compounds, metal salts or esters of thiodipropionic acid,

nited States Patent 9 3,459,703 Patented Aug. 5, 1969 ice dialkyl sulphides, salts or esters of dialkyldithiocarbamates, dialkyldithiophosphoric acid or salts or esters thereof, alkyl or aryl phosphites or thiophosphites, salts or esters of phosphorous oxyor thioacids, or esters of boric acid, ultra-violet light absorbers, soaps, plasticisers, antistatic agents, pigments, dyes and fillers.

The incorporation of the chelate complexes of the invention provides a considerable increase in the resistance of the polymer to degradation by light. In many cases the stability so provided is not significantly reduced by treatments such as washing of the stablised polymer.

As aromatic oximes from which the chelate complexes are derived there may be mentioned oximes of carbonyl compounds of the type for example Ar.CO.Y wherein Ar is an aromatic radical such as phenyl, ozor B-naphthyl which carries a phenolic hydroxyl group in the ortho position to the carbonyl group and may optionally carry other substituents such as a hydrocarbon group for example an alkyl group such as methyl, isopropyl or tert.-butyl, nonyl, lauryl or tert.-octyl, a-Il'lBthYlCYClOhCXYl or phenyl, a halogen atom such as chlorine, an alkoxy group such as methoxy or octyloxy, or a nitro group, and Y is a hydrogen atom or an optionally substituted hydrocarbon radical, such as an alkyl group for example methyl, or 3-hydroxyethyl, a cycloalkyl group for example cyclohexyl, or an aromatic radical for example phenyl, :xor fi-naphthyl, substituted phenyl such as hydroxyphenyl, or a heterocyclic radical such as furyl, pyridyl or thienyl.

The phenolic hydroxyl group and the oxime group must be positioned so that chelation is possible, the metal atom replacing the hydrogen atom of the phenolic hydroxyl group and being chelated with the nitrogen atom of the oxime group. The hydroxyl group may for example be in a position ortho to the point of attachment on the aromatic ring of the carbonyl group from which the oxime group is derived and the oxime in the syn-configuration, with respect to Y.

Superior stabilisation effects are in general obtained by the use of chelate complexes derived from ketoximes rather than from aldoximes, i.e. from oximes obtained from carbonyl compounds of the type Ar.CO.Y where Y is not a hydrogen atom, and particularly from ketoximes derived from a carbonyl compound wherein Y is aliphatic or cycloaliphatic, e.g. alkyl, substituted alkyl or cycloalkyl. Superior stabilisation is also in general obtained, especially when Y is chosen from one of the preferred classes of groups, by the use of oximes derived from carbonyl compounds of the formula Ar.CO.Y wherein Ar is a hydroxyl substituted phenyl nucleus rather than for example a hydroxyl substituted naphthyl nucleus.

Particularly effective stabilisation is obtained by the use of cobalt and, especially, nickel chelate complexes.

In the chelate complexes used in the process of the invention one molecular proportion of the metal ion is associated with a number, equal to the valency of the metal, of molecular proportions of the ligand (that is the oxime molecule from which one atom of hydrogen is lost).

Examples of chelate complexes which may be used are nickel bis-complexes, chromium tris-complexes and cobalt tris-complexes of syn-methyl Z-hydroxy-4-methylphenyl ketoximes, syn-phenyl 2-hydroxy-4-heptoxyphenyl ketoxime, syn-2-hydroxynaphthylaldoxime, syn-methyl 2-hydroxy-5-tert.- octylphenyl ketoxime, syn-phenyl Z-hydroxynaphthyl ketoxime, syn-methyl 2-hydroxy-5-methylphenyl ketoxime and syn-methyl 2-hydroxy-5-nitrophenyl ketoxirne.

Some of the chelate complexes of particular value in the process of the invention are new compounds and represent a further feature of the invention according to which there are provided as new compositions of matter chelate complexes of nickel, cobalt or chromium with aromatic ketoximes containing a phenolic hydroxyl group.

The chelate complexes may be prepared by any conventional means employed in the manufacture of chelate com: plexes in general. For example a solution of a salt of the metal is reacted with the aromatic oxime in appropriate proportions, that is so that there is used a molar ratio of oxime to metal salt approximately equal to the valency of the metal in the salt. The reaction is preferably carried out in a solvent such as ethanol or water, the reaction mixture being heated if necessary. The chelate complex is then isolated in conventional manner, for example by filtration in the usual case where it is insoluble in the solvent.

Suitable salts to :be used in preparation of the chelate complex are the acetate, chloride, sulphate or nitrate. In those cases in which a suitable salt of the metal in the desired valency state cannot conveniently be used the salt may be prepared in situ from a salt of the metal in another valency state, for example cobaltous salts are used in presence of hydrogen peroxide to furnish cobalt triscomplexes.

Two or more of the chelate complexes may be used in conjunction in the process of the invention and, particularly when derived from diflFerent metals such as nickel and cobalt, may show a synergistic effect leading to enhanced stability of the polymer.

The invention is illustrated but not limited by the following examples in which all parts and percentages are by weight.

Example 1 TABLE I Percent strength Goncentraretained after Stabiliser tion, percent 874 hours Nickel syn-m ethyl Z-hydroxy-d-methylphenyl ketoxime 0. 100 Do 0. 2 83 2-hydroxy-4octylbenzophenone 0. 5 64 The chelate complex used above is prepared as follows:

A solution of 24.8 parts of nickel acetate in 500 parts of ethanol is added to a solution of 33 parts of syn-methyl- 2-hydroxy-4-methylphenyl ketoxime in 90 parts of ethanol. The nickle complex is precipitated immediately. The reaction mixture is heated at the boil for 1 hour and after cooling the product is filtered 01f, Washed with parts of ethanol and dried. 37 parts of the nickel complex are obtained.

The chelate complex may also be prepared from nickel sulphate and the sodium salt of 2-hydroxy-4-methylphenyl ketoxime in water, the insoluble complex being isolated as above.

By either of the above procedures the nickel complexes used in the following examples may be prepared.

In the case of the cobalt tris-complexes the following general procedure may be used:

A solution of 8.3 parts of cobaltous acetate in parts of methanol is mixed with a solution of 16.5 parts of synmethyl Z-hydroxy-S-methylphenyl ketoxime in 100 parts of methanol. 10 parts of aqueous hydrogen peroxide (100 volume) are added slowly and the solution is heated to the boiling point and maintained at that temperature for 18 hours. The solution is cooled and the insoluble complex isolated by filtration, washed with methanol and dried at 100 C.

Example 2 Polypropylene is blended, as in Example 1, with 0.1% of 1,1,3 tris(2 methyl 4-hydroxy-5-tert.-butylphenyl)- butane, 0.5 diphenyl iso-octylphosphite (mix A) or 0.5% trilauryltrithiophosphite (mix B), 0.5 of nickel syn-methyl-2-hydroxy-4-methylphenyl ketoxime and 0.4% of calcium stearate and spun at C. The yarns are exposed to the xenon-arc as before.

Percent strength retained after 874 hours Mix A 100 Mix B 88 Example 3 Polypropylene is blended with 0.1% of 1,1,3-tris(2- rnethyl-4-hydroxy-S-t-butylphenyl)butane, 0.5% of trilauryltrithiophosphite, 0.4% of calcium stearate and 0.5 of stabiliser, and spun at 210 C. and draw ratio 4:1. The resulting yarns are then exposed to a 1000 Watt xenon arc lamp or to daylight under glass. The average toughness of the yarns, defined as tenacity gm./ den.) percent extension at break 2 l0- is determined before and after exposure.

TABLE II Percent toughness retained after- 000 hours 9 weeks I exposure to exposure Stabrhser xenon arc in daylight None 20 47 2-hydroxy-4-octyloxy-beuzophenone 32 40 Nickel bis(syn-methyl-2-hydroxy-4-methylphenyl ketoxime) 73 82 Example 4 Polypropylene is blended with 0.1% of 1,1,3-tris(2- methyl-4-hydroxy-S-t-butylphenyl)butane, 0.5% of dilauryl thiodipropionate, 0.4% of calcium stearate and 0.5 of stabiliser, and spun at 225 C. and draw ratio 4:1. The resulting yarns are then exposed to a 1000 watt xenon-arc and to daylight under glass. The average toughness of the yarns, defined as tenacity (gm./den.) percent extension at break 2 10' is determined before and after exposure.

Example 5 Polypropylene is blended with 0.1% of 1,1,3-tris(2- methyl-4-hydroxy-5-t-butylphenyl)butane, 0.4% of calcium stearate, 0.5% of a hydroperoxide decomposer and 0.5 of stabiliser, spun at 190 C., and draw ratio 8:1. The resulting yarns are then exposed outdoors on aluminium frames inclined at an angle of 45 to the vertical facing south in Florida.

Polypropylene is blended with 0.1% of nickel bis(synmethyl 2-hydroxy-4-methylphenyl ketoxime), 0.25% of hydroperoxide decomposer and 0.4% of calcium stearate, and spun at 190 C. and draw ratio 8:1. The resulting yarns are exposed to a 1000 watt xenon-arc lamp and the tensile strengths of the yarns measured before and after exposure.

TABLE V Percent strength retained after 269 hours Hydroperoxide decomposer: exposure Dilauryl thiodipropionate 45 Trilauryl trithiophosphite 43 Zinc dibutyl dithiocarbamate 87 Zinc di-isopropyldithiophosphate 60 Example 7 Polypropylene is blended with 0.1% of 1,1,3-tr'is(2- methyl-4-hydroxy-S-t-butylphenyl)butane, 0.5% of dilauryl thiodipropionate, 0.4% of calcium stearate and 0.5% of stabiliser, and spun at 190 C. and draw ratio 8:1. The resulting yarns are then exposed to a 1000 watt xenon-arc lamp, and the tensile strengths of the yarns determined before and after exposure.

TABLE VI Percent strength retained after 787 hours Stabiliser: exposure Cobalt tris(salicylaldoxime) (A) 43 Nickel bis(salicylaldoxime) (B) 61 0.25% of A+0.25% ofB 67 Example 8 Polypropylene is blended with 0.1% of 1,1,3-tris(2- methyl-4-hydroxy-5-t-butylphenyl)butane, 0.5% of dilauryl thiodipropionate, 0.4% of calcium stearate and 0.5% of stabiliser, and spun at 225 C. and draw ratio 4:1. The resulting yarns are then exposed to 1000 watt xenon-arc lamp, and the average toughness of the yarns determined before and after exposure.

TABLE VII Percent toughness retained after 600 hours U.V.-stabilizer: exposure Nickel bis (syn-methyl-2-hydroxy-4-methylphenyl ketoxime) 52.8 Chromium tris(syn-methyl-2-hydroxy-4-methy1- phenyl ketoxime) 29.2 Chromium tris(syn-methy1- 2 hydroxy-S-chlorophenyl ketoxime) 18.1

Control without stabilisers 13.3

The chromium tris(syn-methyl 2-hydroxy-4-methylphenyl-ketoxime) used above is prepared by heating at 100 C. with stirring for 18 hours a mixture of 24.8 parts of syn-methyl 2-hydroxy-4-methylphenyl ketoxime, 6.65 parts of chromic chloride (hexahydrate) and 50 parts of urea. After cooling the chelate complex is collected by filtration, ground to a powder, washed thoroughly with water, and dried at 60 C.

By a similar procedure the chromium tris(syn-methyl Z-hydroxy-S-chlorophenyl ketoxime) is prepared from the corresponding ketoxime.

Example 9 The procedure of Example 7 is repeated using the stabilisers listed below. The strength retentions after 458 hours exposure are determined.

TABLE VIH Percent strength Stabiliser: retention Nickel bis(syn-methyl 2-hydroxy-4-methylphenyl ketoxime) 89 Nickel bis(syn-methyl 2,4-dihydroxyphenylketoxime) 26 Nickel bis(syn methyl 2 hydroxy-3-t-butyl-5- methylphenyl ketoxime) 82 Nickel bis(syn-phenyl 2-hydroxy-5-chlorophenyl ketoxime) 32 Example 10 The procedure of Example 9 is repeated using the stabilisers listed below.

TABLE IX Percent strength Stabiliser: retention Nickel bis(syn-methyl 2-hydroxy-4-methylphenyl ketoxime) Nickel bis(syn-methyl 2-hydroxy-5-methylphenyl ketoxime) Nickel bis(syn-methyl 2-hydroxy-phenyl ketoxime 92 Example 11 Polypropylene films (5 10" in. thickness) containing 0.5% of stabiliser, 0.5% of dilauryl thiodipropionate and 0.1% of 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)- butane are immersed in trichloroethylene at room temperature for various times. The concentration of stabiliser remaining in the polypropylene is monitored by U.V. absorption spectra, optical densities being measured at the max. of this stabiliser. The results indicate the superior Wash-fastness of the nickel complexes over a commercial U.V. stabiliser.

of 3,5 di-t-butyl-4-hydroxybenzyl-di-n-0ctadecylphosphonate and extruded at 280 C. 0.02" thick plaques are then TABLE X Optical density after immersion for- Background Stnbihser am, (my) min. min. min. optical density Nickel bis(syn-phenyl 4-dodecyloxy-2- hydroxyphenyl ketoxime) 380 0. 65 0. 66 0. 70 0. 3 Nickel bis(syn-phenyl 4-he tyloxy-2- hydroxyphenyl ketoxime 380 0. 83 0. 63 0. 53 0. 3 2-hydroxy-4-oetyloxybenzoplienone 325 1- 9 0. 3 0.

The preceding Example 9 is repeated with the nickel complex stabiliser used above.

TABLE XI S tabiliser Nickel bis(syn-phony] 4-dodecyloxy-2-hydroxyphenyl ketoxime) Nickel bis(syn-phenyl 4-heptyloxy-2-hydroxyphenyl ketoxime) Example 12 Tensile strength (in gJdenier) after exposure to 1,000 watt xenon are lamp Wash treatment Stabiliser 156 hours 344 hours None A 4, 100 4, 250 B 4, 300 3, 250 (a) A 4, 450 4, 200 B 4, 200 2, 400 (b)- A 4, 100 2, 000 B 3. 650 11, 150

Example 13 Polyhexamethyleneadipamide containing 2% of titanium dioxide is blended with 0.1% of stabiliser, 0.05% of 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane and 0.1% of trilauryltrithiophosphite and spun on a gravity melter. The resulting yarns are given a typical commercial finishing treatment (heat-setting at 200 C. for seconds on a threadline apparatus, chlorite-bleaching and bisulphite clearing) and exposed to a 100 watt xenon-arc lamp for 24 hours and the tensile strength of the yarns measured before and after exposure.

TABLE XIII Percent loss in Stabiliser: strength Nickel bis(syn-methyl-Z-hydroxy 4 methylphenyl ketoxime) 35.8 2-hydroxy-4-t-octyloxybenzophenone 36.4

0.005% of manganous acetate (commercially used stabiliser) 4.3.5

Example 14 Poly-4-methylpentene-1 is blended with 0.5% of stabiliser, 0.25% of 2,6-di-t-butyl-4-methylphenol and 0.25%

Percent strength reteni ion after exposure to 1,000 watt xenon-arc lamp for 513 hours 782 hOlJl'S exposed to a 1000 watt xenon-arc lamp. The time in hours necessary to absorb 0.1% of oxygen is determined by infra-red spectroscopic measurements on the rate of formation of carbonyl groups as shown by carbonyl absorption bands.

TABLE XIV Stabiliser: Hours None 700 2-hydroxy-4-octyloxybenzophenone 950 2 hydroxy bis(syn-methyl 2 hydroxy-4- methylphenyl ketoxime) 1300 Example 15 parts of polyvinyl chloride are blended with 2 parts of a commercial alkyl thio tin stabiliser, 1 part of ethyl palmitate (a lubricant) and 0.1 part of stabiliser. Sheets are moulded at C. and exposed to daylight under glass. The change in colour is monitored against the Standard W001 Blue scale (BS. 1006: 1955), which gives ratings of 1-8, 1 being a large change and 8 the minimum change in colour.

TABLE XV Colour chan e Stabiliser: ratiii g None Nickel bis(syn-methyl 2-hydroxy-4-methylphenyl ketoxime) Example 16 100 parts of polyvinyl chloride are blended with 4 parts of dibasic lead phosphite, 1 part of ethyl palmitate and 0.1 part of stabiliser. Sheets are moulded at 150 C. and exposed to daylight under glass, the change in colour bemg compared against the Standard W001 Blue Scale.

TABLE XVI Colour change Stabiliser: rating None 5-6 Nickel bis( syn methyl 2 hydroxy 4 methylphenyl ketoxime) We claim:

1. A polymeric composition stabilized against light which comprises a polymer selected from the group consisting of polypropylene, poly-4-methyl-pent-l-ene, polyvinyl chloride and polyhexamethylene adipamide and a chelate complex of an aromatic oxime containing a phenolic hydroxyl group with a metal replacing the hydrogen atom of the phenolic hydroxyl group and being chelated with the nitrogen atom of the oxime group, said metal being selected from the class consisting of nickel,

cobalt and chromium, said aromatic oxime moiety being derived from a ketoxime of the formula wherein Ar represents a member selected from the class consisting of substituted orthohydroxyphenyl, substituted orthohydroxy-a-naphthyl and substituted orthohydroxy- ,B-naphthyl wherein the substituent on the phenyl and naphthyl moieties is selected from the class consisting of alkyl, phenyl, halogen, alkoxy and nitro, and Y is a member selected from the class of alkyl, hydroxyalkyl, cycloalkyl, phenyl, and uor B-naphthyl.

2. The polymeric composition of claim 1 wherein the polymer is polypropylene.

3. The polymeric composition of claim 1 wherein the chelate complex is present in an amount between 0.01 and 5.0% of the Weight of the polymer.

4. The polymeric composition of claim 1 wherein the chelate complex is present in an amount between 0.2 and 1.0% of the weight of the polymer.

5. The polymeric composition of claim 1 wherein-the metal is nickel.

References Cited UNITED STATES PATENTS 2,493,597 1/1950 Rothrock 26045.7 2,625,521 1/1953 Fischer et al. 26023 2,824,847 2/1958 Fath 26023 3,001,969 9/1961 Tholstrup et al. 26045.75 3,107,232 10/1963 Matlac-k 260--4S 75 3,160,597 12/1964 Costain et al. 26021 3,163,492 12/1964 Thomas 8-55 3,203,752 8/1965 Mills et al. 855 3,255,136 6/1966 Hec-ker 26023 3,278,483 10/1966 Wright 26045.85 3,280,070 10/1966 Battista et al. 26045.85

OTHER REFERENCES Technical Bulletin No. 193, pub. Apr. 23, 1963, pp. 4, 7 and 11. Publishers: I.C.I./Organics/Inc., Providence, R.I., subsidiary of Imperial Chemical Industries Limited.

20 DONALD E. CZAJA, Primary Examiner V. P. HOKE, Assistant Examiner @2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 459 703 Dated August 5, 1969 Inventor(s) Peter James Briggs and Ronald James Hurlock It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, "Claims priority, application Great Britain, Oct. 10, 1966." should read --Claims priority, application, Great Britain, Oct. 21, 1965.--. Column 3, line 65, "nickle" should read --nickel--.

S'IGNED AN.) SEALED JAN 204970 {SI SAL) Afloat:

Edward M. Fletcher, Ir,

Attesting Officer WILLIAM E. soauYLsR. JR-

Gommissioner of latents 

